Question: What group had effect on Congress of Vienna?
Paraphrase: What gather had impact on Congress of Vienna?
SPARQL (Wikidata):  select distinct ?obj where { wd:Q46362 wdt:P1542 ?obj . ?obj wdt:P31 wd:Q16887380 } 
Answer: Border Kingdom of Saxony-Kingdom of Prussia 1815, borderstones Belgium-Prussia